Carbon nanotube arrays for optical design of amorphous silicon solar cells

Effective light trapping is essential for the conversion efficiency increase in thin film solar cells. Vertically aligned multiwalled carbon nanotubes (MWNTs) arrays with proper spacing form an ideal light trapping structure. In this work, we have demonstrated feasibility of the incorporation of MWNTs as back contact into amorphous silicon solar cells. Intrinsic amorphous silicon films were uniformly deposited onto vertically aligned MWNTs arrays. Scanning Electron Microscopy (SEM) was used to investigate the surface morphology of our films. The film surface area exposed to light was found to be increased dramatically due to the high-aspect ratio of MWNTs. Our findings open up a new way of managing light in thin film silicon solar cells by controlling the nano-geometry of MWNTs on substrates.